Pickled Watermelon Rind

I found this recipe on Oprah's website, of all places. It's adapted from the book Vegan Soul Kitchen by Bryant Terry. It goes nicely in a salad with watercress, spinach and rocket leaves.
I made three-quarters of the amount below, as I didn't have enough rind to make the full amount.

Ingredients:
Rind from a medium-size watermelon
3 1/4 cups (780ml) cane sugar divided
3/4 cup (180ml) sea salt
4 sticks cinnamon
2 Tbsp. whole cloves , divided
2 large oranges , thinly sliced
4 lemons , thinly sliced
1 cup (240ml) apple cider vinegar
1 cup (240ml) distilled white vinegar (I used extra acv instead)

Directions:
Prepare the watermelon rinds by removing the green skin with a peeler or utility knife. Cut away most of the red flesh with a knife, but leave a thin coat. Cut as much of the rind as possible into 1/2-inch (1cm) cubes (many of the pieces will be odd shapes) until you generate 10 cups (2.4 litres) of rind. Set aside.

In a large stockpot over medium-low heat, make a brine by combining 12 cups (2.9 litres) water with 1/4 cup (4 tbsp) sugar, salt, 2 cinnamon sticks, and 1 tablespoon cloves. Stir well until the sugar and salt are completely dissolved. Remove from heat and cool. Transfer watermelon rind to the brine. Place a small plate on top of the rinds to ensure that they are completely covered in water and don't float to the top. Soak overnight.
Drain the rinds and rinse several times with cold water.

Combine the rinds with enough cold water to just cover them in a stockpot. Bring to a boil, lower heat to medium, then simmer until the pieces are tender but still crisp, about 10 minutes. Drain and set aside.

Combine orange and lemon slices, vinegars, and remaining sugar, cinnamon sticks, and cloves with 3 cups (720ml) water in stockpot. Bring to a boil over high heat. Add the rinds, bring back to a boil, reduce heat to low, cover, and simmer for 10 minutes.
Drain the rinds, catching the liquid in a bowl, and set them aside. Add the liquid back to the stockpot, bring to a boil over high heat, and reduce until it thickens slightly, 12 to 15 minutes. Transfer syrup to a metal bowl (or saucepan); let cool.

Place syrup and rinds in a plastic covered container; store in the refrigerator for up to 2 weeks.

Original recipe taken from here.